Concrete block wall

[mrazntre]

Hi eeryone, this is my first post.
I've searched this forum for some answers to my questions, but I've only been able to brush the surface. My construction experience is minimal and is mostly with electrical.

Here's the situation:

My friend wants to build a concrete block wall fence in his backyard. The rear of his property butts up to government land that is supposed to be turned into a street (never happened). The dirt appears to have a crown in it so that my friend's lot is actually 1' to 2' higher than the gov't land.

1) how would we go about setting a foundation for the block wall in order to prevent slippage? from my guess, we would just dig down to what would be considered "street level" and start there.

2) how do I build a concrete block wall? :oops:

Thanks in advance.

[roger g]

Depends on where you live. Your footings must be below frost level which means if you live in most of Canada you must dig down 300 feet. A couple of feet (elevation difference)probably won't make much difference but it depends on where the slope is in relation to the property line and where you want to put the wall. You haven't said how high the wall will be be. 2 feet? 10 feet? Depending on how high the wall is and how long the wall is you might need pilasters (thicker spots) every so often to strengthen the wall. Might need rebar also. "S" shaped walls look nice and are self supporting plus you have lots of hidee holes to plant stuff.
How do you lay block? Put lots of sticky stuff on them and put them on top of each other.


roger

[mrazntre]

hey roger,

oops, I neglected the details...

I live in Southern California, so there's no frost line to worry about.
The property ends where the drop off begins, it's not a slope and looks like a natural curb, but its eroding away with our current rainfall. I want to put the wall right at that edge.

The wall is limited to 6' high and the length of the wall is going to be about 66', just a straight shot from one end to the other. I don't believe that we'll be needing pilasters.

My main questions is how I would connect the concrete blocks (the foundation - how wide and deep? Dimensions please) to the ground so that the wall will resist slippage.

[roger g]

I would go down below the lower grade as you suggested for the footings. AS to the footing design ( which is really simple) and the wall thickness I would contact your building inspector because he is the guy you are going to please regardless whatever we say.
I bet you will need pilaster because a 66 foot wall isn't too stable. I don't think it would be too hard to push over. I really mean that. Pilasters every so often gives lateral (side to side) strength. Blocks are attached to the concrete footing by mortar which is the same stuff that sticks the blocks together. Punch in block laying on the internet and I'm sure you will find some how to sites.

roger

[mrazntre]

Thanks for the help thus far Roger.

How many feet until you need a pilaster?
Something like 1 per every 10 linear feet?

(I read the pilaster question wrong in your first post, I thought it only had to do with vertical rigidity)

[roger g]

To be honest I don't really know. It depends on how far below grade it is. (doesn't apply to you but would if you were building a basement) Wind, earthquakes(now that would apply to you) How thick the wall is 6,8,10 inch and what your building code says. Maybe you won't need them at all but on some walls I saw years ago (haven't seen a new block wall in years) the pilasters looked about 20 feet apart.

roger